force triple-buffering for AMD cards?

Anyone have any idea how to enable triple-buffering in games that do not explicitly provide the option? Eg, Portal, which runs GREAT in Wine, save for framerate issues when using v-sync that would easily be solved by triple-buffering.

On Windows, you can use neat utilities such as RadeonPro and D3DOverrider, but since we stubborn linux gamers need to emulate through a Wine layer I seriously doubt these convenient hacks are an option...